A conventional processing device within an electrophotographic image forming apparatus is provided with a charger for charging a photosensitive member. Such a conventional charger includes a wire electrode to which a high voltage is applied, a grid electrode disposed between the wire electrode and the photosensitive member, and a shield electrode covering the wire electrode from a side opposite to the grid electrode.
In recent years, there has been a demand for the photosensitive member to move fast relative to the charger for the purpose of speeding up image formation. As a consequence, the charger is also required to have an improved charging capability.
To this effect, there is proposed a charger in which the wire electrode is disposed at a position upstream of the center within the shield electrode in a direction in which the surface of the photosensitive member moves in order for the surface of the photosensitive member to be charged in a prompt manner.